So, I went back (rainy morning) and used the "fudged" numbers, the ones used in the diagram. I found an (presumably) accurate layout for the pyramids
Some things I found.
1) The radius for the arc described by the pyramids has an azimuth of 307.4º.
2) The length of that radius is 2,348 meters.
So, the azimuth provided by the diagram is off by 0.5º. For reference, that is the angular diameter of a full Moon. The length? I have no idea what
the significance of 2,960 meters is since it has nothing to do with the arc but using it I found:
In the diagram, the apex of Mekaure seems to offset about 0.5º to the north from where it should be. Kahfre is 0.4º off, and Khufu is 0.4º off. So,
everything has been shifted to the north a bit, but with some consistency. Could be a matter of mapping errors, on either side.
So how about the locations of the setting stars? Using Collins' date of 2,600 BCE, we find that again, his numbers are close, but off by about 0.5º
for Gamma and Delta. So, considering the offset of the two corresponding pyramids, they would indeed line up quite well. However, the position which
Collins gives for Epsilon would seem to be off by a greater amount.
But Epsilon has moved since 2,600 BCE. Compared to the other stars of the constellation it's much closer to us so it shows more proper motion. In
2,600 BCE it was at 20h 44' 24", 33º 42' 36". This means that when it was 2º above the horizon it would have been something less than 0.3º to the
south of where it would have been without its proper motion. Close to the location of the third pyramid.
So, guess what? It seems (I haven't rechecked my work, and won't) the alignment actually is pretty close. What it means, if anything, I have no idea.
While easily recognizable, Cygnus does not contain any particularly striking asterisms (unlike the stars of Orion's belt). It's a bit puzzling too,
why Deneb, by far the brightest of the stars in the group is not represented.
edit on 4/30/2016 by Phage because: (no reason given)